Question

Two elements $$'P'$$  and $$'Q'$$  combine to form a compound. Atomic mass of $$'P'$$  is 12 and $$'Q'$$  is 16. Percentage of $$'P'$$  in the compound is 27.3. What will be the empirical formula of the compound ?

A. $${P_2}{Q_2}$$
B. $$PQ$$
C. $${P_2}Q$$
D. $$P{Q_2}$$  
Answer :   $$P{Q_2}$$
Solution :
Element % No. of moles Molar ratio Whole no. ratio
$$P$$ 27.3 $$\frac{{27.3}}{{12}} = 2.27$$ 1 1
$$Q$$ 72.7 $$\frac{{72.7}}{{16}} = 4.54$$ 2 2

Empirical formula $$ = P{Q_2}$$

Releted MCQ Question on
Physical Chemistry >> Some Basic Concepts in Chemistry

Releted Question 1

$$27 g$$  of $$Al$$  will react completely with how many grams of oxygen?

A. $$8\,g$$
B. $$16\,g$$
C. $$32\,g$$
D. $$24\,g$$
Releted Question 2

A compound was found to contain nitrogen and oxygen in the ratio $$28 gm$$  and $$80 gm$$  respectively. The formula of compound is

A. $$NO$$
B. $${N_2}{O_3}$$
C. $${N_2}{O_5}$$
D. $${N_2}{O_4}$$
Releted Question 3

The largest number of molecules is in

A. $$36\,g$$  of water
B. $$28\,g$$  of carbon monoxide
C. $$46\,g$$  of ethyl alcohol
D. $$54\,g$$  of nitrogen pentoxide
Releted Question 4

The total number of electrons in one molecule of carbon dioxide is

A. 22
B. 44
C. 66
D. 88

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